The state leads the nation in reporting disease outbreaks linked to pools and drinking water, a CDC study finds.

Hours after a group of high school cheerleaders took a dip in the pool of their Tampa hotel last year, some complained of itchy skin. Within days, 53 people who swam there, and 34 guests at a nearby hotel, reported a red bumpy rash covering their arms and legs.

Hillsborough County health officials knew they had an outbreak on their hands and closed the pools.

They found the pools had overloaded filtration systems and inadequate disinfection. Low chlorine and pH levels provided a breeding ground for the bacteria that caused the painful rash in the March 2001 outbreak.

That scenario is becoming more common in Florida and across the country, as people who swim are far more likely to get sick from parasites and bacteria in water than they were a decade ago.

Outbreaks of waterborne illnesses roughly doubled in the United States in a three-year period ending in 2000. Florida leads the country in the number of reported incidents, according to a study released Thursday by the Centers for Disease Control and Prevention. Of 59 disease outbreaks nationally from 1999 and 2000 in "recreational waters" -- pools, hot tubs and water parks -- Florida had 14, the CDC said.

Illnesses from contaminated drinking water are up, too, the report said. And Florida also reported the most outbreaks of sickness in that category. Of 39 drinking water outbreaks in 1999 and 2000, Florida had 15.

Poor personal hygiene and shoddy maintenance and treatment are the leading culprits in the rise in cases of swimming pool-borne parasites such as cryptosporidium, the CDC said. Exposure to the parasite can cause severe diarrhea, nausea and fever.

Though Florida leads the country in disease outbreaks, Shirlene Lee, co-author of the CDC study, cautioned that good surveillance techniques might partly explain the increase.

"Florida is a state with very good surveillance, so where you tend to see numbers that look higher is actually when there is better reporting," Lee said.

As for the increase in drinking water contamination, Lee pointed to the nation's increasing dependence on private wells as one reason.

"There are more people who are drinking well water each year. There are approximately 30,000 new wells drilled each year" in the United States, Lee said.

An estimated 2,068 people got sick, and two died, nationwide in 1999 and 2000 because of illnesses from drinking water, the CDC said. Another 2,093 people fell ill from contamination in pools, hot tubs and water parks.

The CDC study detailed one 1999 Florida case in which a household well was located 10 feet from a chicken coop and in range of runoff containing the birds' waste. Well users were sick for about 60 days. Dr. Roberta Hammond, food- and water-borne disease coordinator for the Florida Department of Health, said disease prevention is a matter of common sense.

"There's certain places where you can minimize the risk. Like in the case with the well by the chicken coop -- there the water should have been placed somewhere else or further away from the chicken coop," she said.

Tampa Water Department director David Tippin said contamination in municipally supplied tap water is much less likely.

"We go to a lot of pains to ensure that. We take thousands and thousands of water samples every year," Tippin said.

Florida's year-round pool and beach culture may be another reason the state ranks so high in number of outbreaks. The state has roughly 750,000 swimming pools, according to officials with the Florida chapter of the National Spa & Pool Institute, a nonprofit swimming pool industry trade association.

David Oxley, the president of the institute's Florida chapter, attributes much of the increase in illness to lax enforcement of basic hygiene standards.

"People who work the water parks and some commercial pools aren't being as diligent as they should be. You go to a hotel and you see a baby in the pool with a diaper on," Oxley said. "Unfortunately, people's bathing habits are not what they used to be."

Poor hygiene increases the risk of cryptosporidium in pools and spas. Called crypto for short, the parasite typically enters the water when babies' diapers leak or people already suffering from diarrhea swim in pools. The parasite, which is especially resistant to chlorine, now accounts for almost 70 percent of water-borne outbreaks, according to Michael Beach, another co-author of the CDC study.

Cryptosporidium is usually killed by "shocking" the pool -- upping chlorine levels drastically. But some pool operators, especially homeowners, may not be aware of that. And that's why public education and better training and licensing requirements for pool service professionals is especially important, experts say.

St. Petersburg recreation manager Gretchen Tenbrock has managed the city's nine public pools for 15 years and said she has never seen an outbreak.

The city's Parks Department includes a three-person team of technicians who routinely test the pools for contaminants. The city's 14 certified inspectors ensure pools are tested before they're opened to the public. Pool staff conduct three more tests before day's end, she said.

During the summer months when swimmers flock to public pools, the city beefs up the number of inspections and pool staff are on high alert.

Despite the 2001 outbreak of pseudomonas folliculitis in the Tampa hotel pools, officials in Hillsborough say such incidents are rare there, too.

One of the factors was the large number of swimmers at once -- students at a cheerleading conference -- who overloaded the pool's filtration system, said Jordan Lewis, Hillsborough County's director of environmental health.

"Hillsborough County has over 1,000 public pools," Lewis said, "and we inspect every one."